The present invention relates to a silver halide photographic material, and particularly to a silver halide photographic material having high sensitivity, decreased residual colors after processing and minor fluctuations in photographic characteristics after continuous processing.
Much effort has hitherto been made to enhance sensitivity of silver halide photographic materials and to decrease residual colors after processing. It has been known that sensitizing dyes used for spectral sensitization greatly affect properties of the silver halide photographic materials. In the sensitizing dyes, the slight difference in structure greatly affects the photographic properties such as sensitivity, fog, storage stability and residual coloration (residual colors), and the use of two or more of the sensitizing dyes in combination also greatly affects the photographic properties. However, it is difficult to predict its effect beforehand. Accordingly, many researchers have hitherto made effort to synthesize many sensitizing dyes and to study the use of many sensitizing dyes in combination, thereby examining their photographic properties. However, it is still impossible to predict the photographic properties in the present circumstances. For the above-mentioned reason, a technique for spectrally sensitizing the silver halide photographic materials at high sensitivity without adverse effects such as fog and residual colors has been desired.
When it is desired that the absorption maximum of the sensitizing dye is shifted to the long wavelength side, a naphthazole nucleus has hitherto been widely used in which a benzene ring is further condensed with a benzazole nucleus. However, a recent strong demand toward enhancement in sensitivity increases the amount of the dye added, while a reduction in a processing waste solution for complying with rapid photographic processing and environmental problems must be complied with. A highly hydrophobic dye such as the naphthazole nucleus-containing dye becomes difficult to meet such demands.
In Japanese Patent Application No. 124612/2000 (corresponding to U.S. Patent Application Publication No. 2002/0058216A1), the present inventors have disclosed that a sensitizing dye in which an azole nucleus having a specific heterocycle condensed is used in place of a naphthazole nucleus is higher in sensitivity and more decreased in residual colors than a naphthazole dye. However, such a dye is much accumulated in a processing solution after processing in principle, so that the problem has become clear that a fatigued processing solution is liable to fluctuate the photographic properties.
An object of the present invention is to provide a silver halide photographic material having high sensitivity, decreased residual colors after processing and minor fluctuations in photographic characteristics after continuous processing.
As a result of intensive investigation, the object of the present invention has been able to be attained by the following:
(1) A silver halide photographic material comprising at least one methine dye represented by the following general formula (I) and at least one coupler represented by the following general formula (X): 
xe2x80x83wherein X1 and X2 each represents an oxygen atom, a sulfur atom, a selenium atom, a tellurium atom, a nitrogen atom or a carbon atom; Y1 represents a furan, pyrrole or thiophene ring which may be condensed with another 5- or 6-membered carbon ring or heterocycle or may have a substituent group; Y2 represents an atomic group necessary for forming a benzene ring or a 5- or 6-membered unsaturated heterocycle, which may be further condensed with another 5- or 6-membered carbon ring or heterocycle or may have a substituent group; a bond between two carbon atoms by which Y1 and Y2 are each condensed with the carbon ring or the heterocycle may be a single bond or a double bond; R1 and R2 each represents a substituted or unsubstituted alkyl, aryl or heterocyclic group; L1, L2and L3 each represents a methine group; n1 represents 0 or 1; M1 represents a counter ion; and m1 represents a number of 0 or more necessary for neutralizing a charge in a molecule; 
xe2x80x83wherein Z1 and Z2 each represents xe2x80x94C(Q3)xe2x95x90 or xe2x80x94Nxe2x95x90; Q1 and Q3 each represents a hydrogen atom or a monovalent substituent group; Q2 represents a hydrogen atom or a coupling release group; and Q1, Q2 or Q3 may be a divalent group, and combine with a multimer, a dimer or more, or a polymer chain to form a homopolymer or a copolymer;
(2) A silver halide photographic material comprising a support having provided thereon at least one silver halide photographic emulsion layer, which contains at least one methine dye represented by the above-mentioned general formula (I) and at least one coupler represented by the following general formula (XX): 
xe2x80x83wherein Q5 represents a substituted or unsubstituted aryl group; Q6 represents a substituted or unsubstituted alkyl group; Q7 represents a hydrogen atom, a halogen atom, an alkoxyl group or an alkyl group; and X represents a hydrogen atom or a group to be released by a reaction with an oxidant of a developing agent;
(3) The silver halide photographic material described in the above (1) or (2), wherein the methine dye represented by the above-mentioned general formula (I) in (1) or (2) is represented by the following general formula (II), (III), (IV) or (V): 
xe2x80x83wherein Y11 represents an oxygen atom, a sulfur atom or Nxe2x80x94R13, wherein R13 represents a hydrogen atom or an alkyl group; V15 and V16 each represents a hydrogen atom or a monovalent substituent group; X11 and X12 each represents an oxygen atom or a sulfur atom; R11 and R12 each represents an alkyl group substituted by an acid group; V11, V12, V13 and V14 each represents a hydrogen atom or a monovalent substituent group; M11 represents a counter ion; and m11 represents a number of 0 or more necessary for neutralizing a charge in a molecule; 
xe2x80x83wherein Y21 represents an oxygen atom, a sulfur atom or Nxe2x80x94R23 wherein R23 represents a hydrogen atom or an alkyl group; V25 and V26 each represents a hydrogen atom or a monovalent substituent group; X21 and X22 each represents an oxygen atom or a sulfur atom; R21 and R22 each represents an alkyl group substituted by an acid group; V21, V22, V23 and V24 each represents a hydrogen atom or a monovalent substituent group; M21 represents a counter ion; and m21 represents a number of 0 or more necessary for neutralizing a charge in a molecule; 
xe2x80x83wherein Y31 represents an oxygen atom, a sulfur atom or Nxe2x80x94R33, wherein R33 represents a hydrogen atom or an alkyl group; V35 and V36 each represents a hydrogen atom or a monovalent substituent group; X31 and X32 each represents an oxygen atom or a sulfur atom; R31 and R32 each represents an alkyl group substituted by an acid group; A31 represents a methyl group, an ethyl group or a propyl group; V31, V32, V33 and V34 each represents a hydrogen atom or a monovalent substituent group; M31 represents a counter ion; and m31 represents a number of 0 or more necessary for neutralizing a charge in a molecule; 
xe2x80x83wherein Y41 represents an oxygen atom, a sulfur atom or Nxe2x80x94R43, wherein R43 represents a hydrogen atom or an alkyl group; V45 and V46 each represents a hydrogen atom or a monovalent substituent group; X41 and X42 each represents an oxygen atom or a sulfur atom; R41 and R42 each represents an alkyl group substituted by an acid group; A41 represents a methyl group, an ethyl group or a propyl group; V41, V42, V43 and V44 each represents a hydrogen atom or a monovalent substituent group; M41 represents a counter ion; and m41 represents a number of 0 or more necessary for neutralizing a charge in a molecule;
(4) The silver halide photographic material described in the above (3), wherein one of R11 and R12 of the methine dye represented by the above-mentioned general formula (II) in (3) is an alkyl group substituted by a carboxyl group, a xe2x80x94CONHSO2xe2x80x94 group, an xe2x80x94SO2NHCOxe2x80x94 group, a xe2x80x94CONHCOxe2x80x94 group or an xe2x80x94SO2NHSO2xe2x80x94 group, and the other is an alkyl group substituted by a sulfo group;
(5) The silver halide photographic material described in the above (4), wherein Y11 of the methine dye represented by the above-mentioned general formula (II) in (4) is a sulfur atom, V15 is a halogen atom, and V16 is a hydrogen atom;
(6) The silver halide photographic material described in the above (3), wherein one of R21 and R22 of the methine dye represented by the above-mentioned general formula (III) in (3) is an alkyl group substituted by a carboxyl group, a xe2x80x94CONHSO2xe2x80x94 group, an xe2x80x94SO2NHCOxe2x80x94 group, a xe2x80x94CONHCOxe2x80x94 group or an xe2x80x94SO2NHSO2xe2x80x94 group, and the other is an alkyl group substituted by a sulfo group;
(7) The silver halide photographic material described in the above (6), wherein Y21 of the methine dye represented by the above-mentioned general formula (III) in (6) is a sulfur atom, V25 is a halogen atom, and V26 is a hydrogen atom;
(8) The silver halide photographic material described in the above (3), wherein one of R31 and R32 of the methine dye represented by the above-mentioned general formula (IV) in (3) is an alkyl group substituted by a carboxyl group, a xe2x80x94CONHSO2xe2x80x94 group, an xe2x80x94SO2NHCOxe2x80x94 group, a xe2x80x94CONHCOxe2x80x94 group or an xe2x80x94SO2NHSO2xe2x80x94 group, and the other is an alkyl group substituted by a sulfo group;
(9) The silver halide photographic material described in the above (8), wherein Y31 of the methine dye represented by the above-mentioned general formula (IV) in (8) is a sulfur atom, V35 is a halogen atom, and V36 is a hydrogen atom;
(10) The silver halide photographic material described in the above (3), wherein one of R41 and R42 of the methine dye represented by the above-mentioned general formula (V) in (3) is an alkyl group substituted by a carboxyl group, a xe2x80x94CONHSO2xe2x80x94 group, an xe2x80x94SO2NHCOxe2x80x94 group, a xe2x80x94CONHCOxe2x80x94 group or an xe2x80x94SO2NHSO2xe2x80x94 group, and the other is an alkyl group substituted by a sulfo group;
(11) The silver halide photographic material described in the above (10), wherein Y41 of the methine dye represented by the above-mentioned general formula (V) in (10) is a sulfur atom, V45 is a halogen atom, and V46 is a hydrogen atom;
(12) The silver halide photographic material described in the above (1), wherein the coupler represented by the above-mentioned general formula (X) in (1) is represented by the following general formula (XI) or (XII): 
xe2x80x83wherein Q11 represents an alkyl group, Q12 represents a hydrogen atom or a halogen atom, and Q13 represents a substituent group containing xe2x80x94SO2xe2x80x94; 
xe2x80x83wherein Q21 represents an alkyl group, Q22 represents a hydrogen atom or a halogen atom, and Q23 represents a substituent group containing xe2x80x94SO2xe2x80x94;
(13) The silver halide photographic material described in the above (1) comprising a support having provided thereon at least one silver halide photographic emulsion layer, which contains at least one methine dye represented by the above-mentioned general formula (II), (III), (IV) or (V) and at least one coupler represented by the above-mentioned general formula (XII);
(14) The silver halide photographic material described in the above (13), wherein one of (R11, R21, R31 or R41) and (R12, R22, R32 or R42) of the methine dye represented by the above-mentioned general formula (II), (III), (IV) or (V) is an alkyl group substituted by a carboxyl group, a xe2x80x94CONHSO2xe2x80x94 group, an xe2x80x94SO2NHCOxe2x80x94 group, a xe2x80x94CONHCOxe2x80x94 group or an xe2x80x94SO2NHSO2xe2x80x94 group, and the other is an alkyl group substituted by a sulfo group;
(15) The silver halide photographic material described in the above (14), wherein (Y11, Y21, Y31 or Y41) of the methine dye represented by the above-mentioned general formula (II), (III), (IV) or (V) is a sulfur atom, (V15, V25, V35 or V45) is a halogen atom, and (V16, V26, V36 or V46) is a hydrogen atom;
(16) The silver halide photographic material described in the above (2) comprising a support having provided thereon at least one silver halide photographic emulsion layer, which contains at least one methine dye represented by the above-mentioned general formula (II), (III), (IV) or (V) and at least one coupler represented by the above-mentioned general formula (XX);
(17) The silver halide photographic material described in the above (16), wherein one of (R11, R21 R31 or R41) and (R12, R22, R32 or R42)of the methine dye represented by the above-mentioned general formula (II), (III), (IV) or (V) is an alkyl group substituted by a carboxyl group, a xe2x80x94CONHSO2xe2x80x94 group, an xe2x80x94SO2NHCOxe2x80x94 group, a xe2x80x94CONHCOxe2x80x94 group or an xe2x80x94SO2NHSO2xe2x80x94 group, and the other is an alkyl group substituted by a sulfo group; and
(18) The silver halide photographic material described in the above (17), wherein (Y11, Y21, Y31 or Y41) of the methine dye represented by the above-mentioned general formula (II), (III), (IV) or (V) is a sulfur atom, (V15, V25, V35 or V45) is a halogen atom, and (V16, V26, V36 or V46) is a hydrogen atom.